Retained products conception

• Retrospective retrieval of sonograms and patient info
• Cases referred for ultrasound for suspected RPOC
• 269 patients met criteria
• Patients with pathologic specimens were included resulting in 35 examinations
• Images independently reviewed by 2 radiologist, blinded to pathologic results

• Presence of color Doppler signal and amount of endometrial vascularity were assessed
• Type 0: Avascular
• Type 1: Minimal vascularity defined as some detectable color Doppler flow in the endometrium but less than in the myometrium in the same image section
• Type 2: Moderate vascularity defined as vascularity equal to or near equal to that in the myometrium in the same image section
• Type 3: Marked vascularity defined as marked endometrial vascularity greater than that in the myometrium in the same image section

• Spectral tracings of vascularity in the endometrium were analyzed
• Highest peak systolic velocities for arterial and venous waveforms were recorded
• Resistive indices (RI) were also calculated for arterial flow

• Thirty-five patients analyzed
• Twenty-six patients underwent trasvaginal ultrasound
• Nine patients underwent transabdominal ultrasound
• Twenty-eight patients had confirmed RPOC
• Seven patients had no RPOC on pathologic examination

• Avascular endometrial echoes were more commonly seen in patients without RPOC.
• The finding of avascularity should be counterbalanced by otherless specific imaging finding

-Presence of an echogenic mass

-Endometrial thickness

-Clinical suspicion for RPOC

• Type 2 vascularity was the most common appearance of endometrial vascularity
• Type 2 was seen only in those with RPOC
• Type 2 vascularity is defined as endometrial vascularity equal to that in the normal myometrium

• Type 3 was only seen in RPOC.
• The cause of highly vascular area in the endometrium is likely related to the placental implantation site
• It is theorized that a retained placenta maintains its vascular connection to the uterus and, when prolonged (>6 weeks), may be associated with hypertrophied peritrophoblastic vessels that communicate via areas of necrosis in the retained placenta.
• Type 3 vascularity may be so exuberant that the color Doppler appearance can mimic a uterine AVM.

Results showed that the presence of an echogenic mass distending the endometrial cavity was not a sensitive finding (29%) in diagnosis of RPOC but had a moderate PPV (80%).

Use a strict definition of an intrauterine mass

-Measurable in 2 planes

-Distinct from the adjacent endometrium

-Distending the endometrial cavity

-Seen in 28% of patients without RPOC

-Seen in 29% of patients with RPOC

Conclusions

-In those with type 0 vascularity, the likelihood of RPOC was less than 50%.

-Even if RPOC are present, the lack of visible vascularity suggests that the contents are predominantly devascularized tissue, it may pass spontaneously or with the help of uterotonics.

-Types 1, 2, and 3 vascularity still have a vascular connection to the uterus and are highly likely to represent RPOC.

-Type 3 vascularity has a large vascular communication with the uterus, which can even be mistaken for an AVM; in such a case, the obstetrician should be made aware of the vascular nature of the lesion and the theoretical risk of bleeding.

-Detection of an intrauterine mass has a moderate PPV for RPOC but is not very sensitive.

Color Doppler and RPOC

• The presence of any vascularity in the endometrium (types 1–3) had a high likelihood of representing RPOC, with a PPV of 96%.
• When type 2 and 3 vascularity studies were considered separately, all had positive findings for RPOC.